SBAS (WAAS) based approach

[atuna99]

Hi everyone,

On my last flight I came across some issues with flying an RNAV GNSS approach into CYTZ. Firstly, my flight started within the EGNOS covered area (LPPD), and availability was as expected, with the GNSS status page on the FMS showing it as in-use. As I left EGNOS, the FMS switched into "NONE" as expected, but it never switched over to WAAS even while being well within coverage. The approach I had chosen (RNAV X for runway 26) was programmed properly, and the Arrival Data paged showed WAAS as well as the correct channel. Just before the IF, the FMS showed a couple of error messages about SBAS provider unavailability and approach not available (see the screenshot for the full messages, as well as the log just in case). I pressed the APPR button still, and I believe the aircraft just followed a geometric profile from the IF down to the runway. 

What did I do wrong here, both in terms of switching between SBAS providers and flying the approach correctly?

Thank you!

Log.txt

[Pils]

4 hours ago, atuna99 said:

What did I do wrong here, both in terms of switching between SBAS providers and flying the approach correctly?

You did nothing wrong insofar as flying from one provider's service area to another is automatic, however there is currently an FAA-induced SBAS outage in the CL-650's sim world so WAAS is unavailable. In this scenario you have to fallback to non-LPV minimums, and hence Baro-VNAV. On an approach with both LPV and non-LPV available the selection is made in the ARRIVAL DATA page under APPR MODE. However, it may also require changing approaches completely if SBAS is required.

[airforce2]

OK, I'm confused here--is WAAS not operative at all in the panel, or is the add-on temporarily simulating a global WAAS outage?

If it's a simulated outage, something like a NOTAM pop-up notification at the FBO would be helpful rather than leaving us to wonder what we might be doing wrong given the lack of documentation on the Challenger's avionics.

 

[Pils]

56 minutes ago, airforce2 said:

OK, I'm confused here--is WAAS not operative at all in the panel, or is the add-on temporarily simulating a global WAAS outage?

The latter, although it was not deliberate.

56 minutes ago, airforce2 said:

If it's a simulated outage, something like a NOTAM pop-up notification at the FBO would be helpful rather than leaving us to wonder what we might be doing wrong given the lack of documentation on the Challenger's avionics.

Feedback appreciated and noted.

Edited January 15, 2023 by Pils

[FYG001]

Hi Pils, would that FAA SBAS NOTAM be connected to 5G and no Radio Altimeter use? 

[Pils]

3 hours ago, FYG001 said:

Hi Pils, would that FAA SBAS NOTAM be connected to 5G and no Radio Altimeter use? 

There’s no real outage or NOTAM.

[richjb]

On 1/14/2023 at 3:57 PM, Pils said:

You did nothing wrong insofar as flying from one provider's service area to another is automatic, however there is currently an FAA-induced SBAS outage in the CL-650's sim world so WAAS is unavailable. In this scenario you have to fallback to non-LPV minimums, and hence Baro-VNAV. On an approach with both LPV and non-LPV available the selection is made in the ARRIVAL DATA page under APPR MODE. However, it may also require changing approaches completely if SBAS is required.

Hi PIls,

Catching up on posts....

Was that FAA-induced SBAS outage a real-world outage simulated concurrently in HS CL650, or was that something random that the sim placed?  

In all my years of actual flying in the CL300/350 or the Lear 45/75, I have never seen a LPV degrade down to LNAV/VNAV or LNAV level of service.  I was actually flying the HS CL650 the same day, and got the same SBAS NOT IN USE message.  I had to go to the ARR DATA page and switch the approach vertical mode from LPV to Baro.  Last time I did that was in the Level D simulator.  And oh by the way, the instructor could not simulate that degradation.  He had lean over the shoulder and tell us that LPV as not available.  Kudos to HotStart for going beyond what a Level D simulator could do, or at the very least the Challenger 300/350 sim. 

Rich Boll

[richjb]

On 1/16/2023 at 5:17 AM, FYG001 said:

Hi Pils, would that FAA SBAS NOTAM be connected to 5G and no Radio Altimeter use? 

SBAS or GPS is not affected by the 5G Radio Altimeter interference issue.  The 5G C-Band is far enough away from the GPS signal to not interfere with it. 

Rich Boll

[Pils]

20 hours ago, richjb said:

Was that FAA-induced SBAS outage a real-world outage simulated concurrently in HS CL650, or was that something random that the sim placed?

Not the latter, but somewhat the former. It was an FAA outage that induced the simulated total WAAS outage, but it wasn't an outage in their real-world SBAS service itself, rather the reporting systems that the FAA uses to publish the service's status to the public via the internet. It's this system that the Hot Start CL-650 relies upon to determine WAAS coverage, signal quality, availability, etc., according to sim aircraft location. Sure, we could have "failed safe" and kept the in-sim WAAS "operational" based on the last reported status, but where's the fun in that?  I think the failure was a nice opportunity for sim pilots to learn a thing or two!

Edited January 31, 2023 by Pils

[richjb]

22 hours ago, Pils said:

Not the latter, but somewhat the former. It was an FAA outage that induced the simulated total WAAS outage, but it wasn't an outage in their real-world SBAS service itself, rather the reporting systems that the FAA uses to publish the service's status to the public via the internet. It's this system that the Hot Start CL-650 relies upon to determine WAAS coverage, signal quality, availability, etc., according to sim aircraft location. Sure, we could have "failed safe" and kept the in-sim WAAS "operational" based on the last reported status, but where's the fun in that?  I think the failure was a nice opportunity for sim pilots to learn a thing or two!

 Gotcha! :-)  It's a nice addition!

Rich